Incomplete success of angioinhibitor therapy in cancer: Estimation of contribution of pro-angiogenic activity of patient thyroid hormone

Despite the obvious promise of the strategy, pharmaceutical angioinhibition has had variable success in clinical cancer management. Thyroid hormone is a potent pro-angiogenic factor. Endogenous circulating levels of proangiogenic thyroid hormone in cancer patients treated with anti-angiogenic drugs may contribute to host resistance to angioinhibition and explain, at least in part, the variable cancer chemotherapeutic responses obtained with anti-angiogenic agents. The chick chorioallantoic membrane (CAM) angiogenesis assay accepts human tumor xenografts and is a system in which individual patient blood samples can be tested in xenograft vasculature for anti-angiogenic content-including thyroid hormone-in the presence of angioinhibitory drug dose escalation. The assay may also be used to screen individual patient tumor biopsy xenografts for susceptibility to angioinhibition.